If you want to play around with a simulated Alto, the ContrAlto simulator from the Living Computer Museum works very well. It is at http://www.livingcomputermus

If you want to play around with a simulated Alto, the ContrAlto simulator from the Living Computer Museum works very well. It is at http://www.livingcomputermuseum.org/Online-Systems/Press.aspx http://www.livingcomputermuseum.org/Online-Systems/Press.asp... I imagine a FPGA-based Alto would be straightforward since there's not a whole lot of hardware. The tricky part is the Alto is very tied to the hardware, so you'd also need to simulate the low-level display hardware, the disk interface, and so forth. There's no real abstraction layer. For instance, the microcode processes each word as it is read from disk, so the disk drive timing is important.